SAO PAULO — A record number of journalists were imprisoned worldwide in 2012 in a “deteriorating environment for press freedom,” a leading media advocacy group said Thursday.

The New York-based Committee to Protect Journalists said in its annual “Attacks on the Press” report that 232 journalists were jailed last year in a “trend driven primarily by terrorism and other anti-state charges levied against critical reporters and editors.” It said the number was the highest since it made its first survey in 1990.

The report said that 70 journalists were killed in the line of duty in 2012. That’s 43 percent more than in 2011.

“When journalists are silenced, whether through violence or laws, we all stand to lose because perpetrators are able to obscure misdeeds, silence dissent, and disempower citizens,” CPJ Deputy Director Robert Mahoney said in a statement. “The battle to control information is an assault on public accountability that cannot go unchallenged.” Governments must prosecute perpetrators and stop those seeking to incapacitate public oversight by blunting critical and probing reporting.”

The report included the committee’s first “Risk List” of 10 countries where the committee identified the most significant “downward trends” in 2012. Those trends include high murder rates and “entrenched impunity” in Pakistan, Somalia, and Brazil and “restrictive laws to silence dissent in Ecuador, Turkey and Russia, as well as the imprisonment of large numbers of journalists on anti-state charges to thwart critical reporting in Ethiopia, Turkey, Vietnam, Iran, and Syria.

The report also noted that 28 journalists were killed in Syria, making it the world’s deadliest place for reporters last year. It was followed by Somalia with 12 journalists killed, and Pakistan with seven, the report said.

The report also criticized Syrian government attempts to suppress independent coverage of the an anti-government uprising. “In addition to disabling phone networks, electricity, and the Internet, authorities have been implicated in malware attacks against reporters and have used torture to extract the online passwords of journalists,” according to the report.

It said that in 2012, four journalists were murdered in Brazil, making the country the world’s fourth deadliest for the press. Three were killed in 2011. All but one of the seven journalists killed in the past two years had denounced official corruption or crime, the report said.

It criticized the large number of lawsuits filed by Brazilian businessmen, politicians and public officials accusing critical journalists of offending their honor or invading their privacy.

In Russia, the press freedom climate that had improved under Dmitry Medvedev deteriorated after Vladimir Putin’s return to the presidency in May 2012, the report said. It said Putin had approved measures to criminalized defamation and to restrict online content.

With 16 unsolved journalist murders in the past decade, Russia has the world’s ninth-worst record for combating deadly anti-press crime, the CPJ said.

In 2012, Turkey “emerged as the world’s leading jailer of journalists,” CPJ said. Most of the 49 journalists imprisoned last year were Kurdish journalists charged with supporting terrorism by covering the views and activities of the banned Kurdistan Workers Party, the report said.

In Iran, 45 reporters and editors were jailed in 2012, the second-highest total in the world.

“Imprisoned journalists are subjected to horrific conditions that include extended periods of solitary confinement, deprivation of medical care, and torture,” the CPJ said.

The other countries on the “Risk List” are Ecuador, Ethiopia, Somalia, Pakistan and Vietnam.